This invention relates generally to printing carrier sleeves removably mountable on flexographic printing cylinders and having printing plates mounted thereon, and more particularly, to a novel printing carrier sleeve that is simply constructed and easily formed.
In the flexographic printing process, flexible printing plates formed of rubber or other elastomeric material are permanently mounted on a printing carrier sleeve. The printing carrier sleeve is then mounted on a printing cylinder for use in a printing operation. Specifically, the printing plates are then inked in order to print on paper or film sheets.
However, because of the permanent mounting of the printing plates, in order to perform a different printing job, the carrier sleeves with the printing plates mounted thereon must be replaced with a different carrier sleeve and printing plates. Therefore, it is required that there be as many carrier sleeves as there are jobs to run.
This, of course, increases the operating expenses since multiple carrier sleeves must be manufactured and stored. Further, since the carrier sleeves are stored in their cylindrical shape, the amount of storage space that is required is great.
Some carrier sleeves are manufactured by helically winding a paper or other tape on a mandrel, such that the wound edges are in abutting relation, and then securing the edges together to form the carrier sleeve. As described in U.S. Pat. No. 3,978,254 to Hoexter et al, it is known to form carrier sleeves from a rectangular sheet of film material whose opposite edges are adjoined to define an inner tube. Then, a strip of plastic tape having an adhesive layer thereon is helically wound about the inner tube to define a first helix thereabout. Thereafter, a second strip of plastic tape having an adhesive layer thereon is wound in the opposite direction about the first helix.
Hoexter et al eliminates the inner tube, and merely forms the helically wound tape structure on a forming mandrel. See also U.S. Pat. No. 5,425,693 to Gardner et al. This is now a conventional manner of forming carrier sleeves.
However, these latter carrier sleeves suffer from several disadvantages. First, a different tooling must be provided for each diameter carrier sleeve. This greatly increases the cost of manufacture. Second, because of the formation only from oppositely wound helically wound tapes, so that there are different layers that form the carrier sleeve, the carrier sleeve tends to de-laminate, that is, the layers tend to separate. Third, because of the helically wound tapes, there are seams between adjacent winds of the tape. These seams can affect a high grade printing operation.